As signal light spots in the coherent optical detection system change with RF signals because of acousto-optic deflection effects

we study the relationship between the spot structure and the detecting efficiency on the basis of a spot overlapping physical model

analyze the effects of beam collimation

active photosensitive surface radius of detectors and optical local oscillator energy matching on the coherent detection efficiency.The computer simulation and experimental tests demonstrate that taking spots with uniformly distributed energy as local oscillator spots is conducive to improving the efficiency of the coherent detection of the overlapping spots when they drift within a certain range

e.g.when the spatial mismatching angle is in the range±0.5rad

the overlapping efficiency declines by less than 5%

and that the system beam collimation is effectively ensured by light spot compression and collimation processing

the energy utilization ratio of overlapping spots is higher and the system optical matching is better.